Vehicle components and assemblies may include interfaces or joints at which different parts or components of the vehicle have been joined together, as may occur during an assembly process associated with the vehicle. For example, a first part of an airplane may be coupled to a second part of the airplane via a joint or an interface between the first part and the second part. Moreover, the first and second parts may be coupled together using one or more fasteners such as nuts and bolts. The interface may be part of an assembly that is sealed or impermeable to a liquid. For example, the interface may join different parts of a fuel tank. Accordingly, a sealant may be applied to portions of the interface, such as the nuts and bolts, to seal any openings or spaces that may be included in the interface.